DEGENERATION* IN THE LARV.E OF GONIONEMA. 1/3 



i 



the nematophores. An account of this process was first given 

 by All man. 1 



In the germ-plasm and ovarian eggs of certain members of the 

 Hydrozoa, Cnnina for example, amcebiform activities commonly 

 occur. Metschnikoff 2 has described and figured many of 

 these. 



It will be remarked that these instances of amcebiform activi- 

 ties are all limited to portions of the individuals or to the earliest 

 stages of unfertilized eggs. Dr. Loeb 3 found in Campanularia 

 that when parts of a colony were brought in contact with a solid 

 object such as the bottom of a dish the hydranths in that part 

 degenerated and the zooids were changed into soft flowing pro- 

 toplasm. The entire individual was involved in this change. 

 The epiderm of the hydranths affected was left quite empty of 

 sarcode, this being used in formation of stolons at other points 

 of the colony. 



The condition in Gonioncina, also is one of complete modifica- 

 tion. The animal undergoes a decided change, losing its char- 

 acteristic shape and appearance, and becoming transformed into 

 a simple multinucleate plasmodium which sometimes exhibits 

 amceboid movements. 



The simplest case of this manifestation of the amceba-like char- 

 acter of the tissues appears in the tendency to fusion, seen in the 

 young polyps of Gotiioncnia. This takes place in the hydra-like 

 larvae which develop from the free-swimming planulse ; these 

 latter have a way of settling down in clusters on the bottom of 

 the vessel in which they were reared, and it is a common thing to 

 see two or three of these larvae quite fused together at the base, 

 so that they appear to be double- or triple-headed monsters. 

 While such larva; frequently live for some time, I have never 

 happened to see any in' an advanced stage of growth ; it is pos- 

 sible that the condition is degenerative, and that it is the result 

 of defective oxidation. 



1 Allman, j. G., 1884., "Amoeboid Protoplasm in Hydroida," Ann. and Mag. 

 Nat. Hist., 3 13. 



2 Metschnikoff, E., 1874, " Embryologische Studien," p. no. 



amceboid cells. 



3 Loeb, Jacques, "On the Transformation and Regeneration of Organs." Am. 

 Jour. Physiology, June, 1900. 



